The process of blood vessel in-growth (angiogenesis) into biomaterials is important in designing materials for implants or tissue engineering. This research seeks to increase the understanding of the process of angiogenesis in degradable and non-degradable biomaterials. From an engineering perspective, this insight will aid in the creation of materials with specific regions having the optimal structural and chemical properties to facilitate controlled angiogenesis. To achieve this end, an ultraviolet excimer laser will be used to create through-holes in currently existing biomaterials. The laser treatment, in addition to the drilling of a through-hole, causes a change in the surface chemistry that will allow the interior of the hole to be targeted for attachment of recently discovered angiogenic biomolecules or matrices. Polymer films of poly-(L-lactic acid), poly-(glycolic acid), PTFE, polypropylene and a fluorinated polyurethane, created by melting or solvation methods, are currently being studied. Through-holes of diameters 10, 50 and 100 microns are cut with the laser. ESCA is being used to characterize the films prior and subsequent to the laser treatment. An in vitro testing system has been designed to test the modified biomaterials using a chick chorioallantoic membrane (CAM) assay. The materials will first be tested in the CAM assay and then later in an in vivo rat model.